Performance-based prioritization for storage systems replicating a dataset

Patent metadata

Field	Value
Publication number	US-12282399-B2
Application number	US-202318341568-A
Country	US
Kind code	B2
Filing date	Jun 26, 2023
Priority date	Mar 10, 2017
Publication date	Apr 22, 2025
Grant date	Apr 22, 2025

Abstract

Prioritizing highly performant storage systems for servicing a synchronously replicated dataset: detecting a communication fault between two or more storage systems that are synchronously replicating a dataset; identifying a preferred storage system for winning mediation, including determining that the preferred storage system winning mediation would result in better performance than other storage systems winning mediation; and requesting, by the preferred storage system, mediation from a mediation target.

First claim

What is claimed is:

1. A method comprising:
detecting a communication fault between two sets of storage systems of a plurality of storage systems that are replicating a dataset; and
based on the detection, determining active membership in the plurality of storage systems using a first set of storage systems of the plurality of storage systems instead of a second set of storage systems of the plurality of storage systems, wherein the first set of storage systems satisfies storage performance criteria better than the second set of storage systems of the plurality of storage systems.

2. The method of claim 1 , wherein determining active membership in the plurality of storage systems includes requesting, by at least one of the first set of storage systems, mediation from a mediation target only after a predetermined delay.

3. The method of claim 1 , wherein determining active membership in the plurality of storage systems includes use of a quorum protocol, and wherein each storage system of the two sets of storage systems corresponds to zero or more votes within the quorum protocol that determines whether a first set of one or more storage systems may detach a second set of one or more storage systems.

4. The method of claim 3 , wherein a respective quantity of votes corresponding to a respective storage system is dependent upon storage system characteristics.

5. The method of claim 4 , wherein a larger number of votes are given to storage systems with performance characteristics above a predetermined threshold and a smaller number of votes are given to storage systems with performance characteristics below the predetermined threshold.

6. The method of claim 3 , further comprising:
determining, by the first set of one or more storage systems, that there is consistent communication among storage systems of the first set of one or more storage systems;
determining, by the first set of one or more storage systems, lack of communication with storage systems among the second set of one or more storage systems, wherein the first set of one or more storage systems is unable to form a quorum; and
determining, by the first set of one or more storage systems, that the second set of one or more storage systems is unable to form a quorum.

7. The method of claim 6 , further comprising:
determining that the first set of one or more storage systems is unable to form a quorum in dependence upon the first set of one or more storage systems including exactly half of the votes for the storage systems synchronously replicating the dataset.

8. An apparatus comprising a computer processor, a computer memory operatively coupled to the computer processor, the computer memory having disposed within its computer program instructions that, when executed by the computer processor, cause the apparatus to carry out steps of:
detecting a communication fault between two sets of storage systems of a plurality of storage systems that are replicating a dataset; and
based on the detection, determining active membership in the plurality of storage systems using a first set of storage systems of the plurality of storage systems instead of a second set of storage systems of the plurality of storage systems, wherein the first set of storage systems satisfies storage performance criteria better than the second set of storage systems of the plurality of storage systems.

9. The apparatus of claim 8 , wherein determining active membership in the plurality of storage systems includes requesting, by at least one of the first set of storage systems, mediation from a mediation target only after a predetermined delay.

10. The apparatus of claim 8 , wherein determining active membership in the plurality of storage systems includes use of a quorum protocol, and wherein each storage system of the two sets of storage systems corresponds to zero or more votes within the quorum protocol that determines whether a first set of one or more storage systems may detach a second set of one or more storage systems.

11. The apparatus of claim 10 , wherein a respective quantity of votes corresponding to a respective storage system is dependent upon storage system characteristics.

12. The apparatus of claim 11 , wherein a larger number of votes are given to storage systems with performance characteristics above a predetermined threshold and a smaller number of votes are given to storage systems with performance characteristics below the predetermined threshold.

13. The apparatus of claim 10 , further comprising computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:
determining, by the first set of one or more storage systems, that there is consistent communication among storage systems of the first set of one or more storage systems;
determining, by the first set of one or more storage systems, lack of communication with storage systems among the second set of one or more storage systems, wherein the first set of one or more storage systems is unable to form a quorum; and
determining, by the first set of one or more storage systems, that the second set of one or more storage systems is unable to form a quorum.

14. The apparatus of claim 13 , further comprising computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:
determining that the first set of one or more storage systems is unable to form a quorum in dependence upon the first set of one or more storage systems including exactly half of the votes for the storage systems synchronously replicating the dataset.

15. The apparatus of claim 13 , further comprising computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:
determining that the second set of one or more storage systems is unable to form a quorum in dependence upon the second set of one or more storage systems including half of the votes for the storage systems synchronously replicating the dataset.

16. The apparatus of claim 9 , wherein determining whether to request mediation from the mediation target is dependent upon the first set of storage systems being unable to obtain a quorum and no other set of the plurality of storage systems being able to obtain a quorum.

17. A storage system comprising a computer processor and a computer memory operatively coupled to the computer processor, the computer memory including computer program instructions that, when executed by the computer processor, cause the storage system to carry out steps of:
detecting a communication fault between two sets of storage systems of a plurality of storage systems that are replicating a dataset; and
based on the detection, determining active membership in the plurality of storage systems using a first set of storage systems of the plurality of storage systems instead of a second set of storage systems of the plurality of storage systems, wherein the first set of storage systems satisfies storage performance criteria better than the second set of storage systems of the plurality of storage systems.

18. The storage system of claim 17 , wherein the computer program instructions further cause the storage system to carry out steps of: responsive to determining that the storage system is not a preferred storage system for winning mediation, requesting mediation from a mediation target, requesting mediation from the mediation target only after a predetermined delay.

19. The storage system of claim 17 , wherein the compu

Assignees

• Pure Storage Inc

Inventors

• Karr Ronald
• Colgrove John
• Ramanarayanan Ganesh
• Grunwald David

Classifications

• G06F3/0689

  Disk arrays, e.g. RAID, JBOD · CPC title

• G06F3/0611

  in relation to response time · CPC title

• G06F3/0619

  in relation to data integrity, e.g. data losses, bit errors · CPC title

• G06F11/1471

  involving logging of persistent data for recovery · CPC title

• G06F3/06

  Digital input from, or digital output to, record carriers {, e.g. RAID, emulated record carriers or networked record carriers} · CPC title